Radcliffe struggles

Radcliffe, the world record holder, looked unlikely to even make the Beijing Games after suffering a stress fracture of her thigh three months ago but vowed to run having finished fourth in the 10,000 metres in 2000 and fifth in the 5,000 in 1996.

Through a mixture of low-impact cross-training and determination she was able to take her place on the start line and looked comfortable enough for the first half of the race.

Like everyone else in the field, she was unable to respond when eventual winner Constantina Tomescu broke clear around the halfway mark but remained well-placed in the chasing pack.

When she stopped twice there were flashbacks to 2004, when a mixture of heat and illness forced her to pull out six kilometres from the end of the Athens race.

The first occasion on Sunday was a natural break and the second an attack of cramp, but by then she had dropped out of contention.

Radcliffe looked determined to complete the distance and, limping, she was given a great ovation by the crowd as she finished 23rd in 2:32.38, 17 minutes slower than her best.

After a post-race hug with compatriot Liz Yelling, Radcliffe sobbed as she left the track.

"I'm not sure what happened, either my leg cramped or I was protecting it but I felt I couldn't use my leg any more," Radcliffe told reporters.

"It felt like someone was stepping on it but when I turned round there was nobody there. It was the same leg (as the fracture) but it wasn't a sharp pain, more a tightening up."

Radcliffe, who also failed to finish in the 10,000 metres in Athens, accepted that her chances of a medal had been slim but she has not ruled out one more try on home soil in 2012.

"I was trying to achieve the impossible because the amount of running I had done wasn't enough and you can't take short-cuts in the marathon," the 34-year-old said.

"It's not the end. We'll keep fingers crossed for 2012. Maybe the Olympics won't happen for me but how hold is Constantina (38)?

"Maybe my body will hold out. I know in London I will have all that support."

38-year-old Tomescu made her move after a large leading group set a plodding early pace and, with nobody choosing to respond, was a minute clear inside the final 10km.

Pre-race favourite Catherine Ndereba of Kenya beat China's Zhou Chunxiu for silver in a down-to-the-wire sprint as around 50,000 patiently-waiting fans cheered the home favourite.

Tomescu, third in the 2005 world championships and world half marathon champion the same year, stretched her lead further over the closing stages to win in two hours, 26 minutes 44 seconds.

Beijing's notoriously muggy weather relented with cool temperatures, an overcast sky and occasional drizzle keeping conditions bearable.

World champion Ndereba, silver medallist four years ago, showed little sign of life in the first part of the race.

She hit the halfway mark in 26th place and briefly faded from the pack only to gather speed again in the closing stages and finish in 2:27.06, a second ahead of Zhou.

Mara Yamauchi sprinted home in sixth to equal the best ever result by a British woman in an Olympic marathon while Yelling was 26th after falling.

American Deena Kastor, bronze medallist in 2004, dropped out clutching her right foot less than 20 minutes into the race while Reiko Tosa, Japan's best hope of collecting their third successive women's marathon gold medal, also failed to finish.